13, 
In the same issue of "The American Journal of Science" Kuenen 
discussed the magnitude involved. From the volume and density of turbid 
water necessary to account for the high velocity indicated by the timing of 
the cable breaks, he calculated a thickness of between 40 and 100 cm. for 
the graded layer of relatively coarse sediment which Heezen and Ewing 
assumed would have been deposited over a wide area south of the cable 
breaks, 
Since the appearance of these papers a series of cores have been 
taken across the southern part of the area affected by the supposed Grand 
Banks turbidity current in hope of confirming the predicted layer of sand 
which should overly more "normal" sediments. 
Three of these contain a layer of graded silt and muddy sand 
overlying foraminiferal clay of abyssal facies, Recent deposition of the 
graded layers is indicated by absence of abyssal sediment overlying them. 
The thicknesses of the layers are 2070 and 130 cm. A fourth core which 
is from the center of the cable break area is composed of 30 cm. of gravel 
and very coarse-grained sand. 
Therefore, it is concluded that the independent evidence afforded 
by the cable breaks together with the evidence from the cores confirming 
the presence of the sand layers add up to proof of the reality of turbidity 
currents as powerful agents of erosion, transportation, and deposition 
of sediment. 
